From bcfec3e09e9062506af2d850d39578a7b577b925 Mon Sep 17 00:00:00 2001
From: hongshuqing <hongshuqing@espressif.com>
Date: Thu, 28 Sep 2023 14:09:12 +0800
Subject: [PATCH] s2 cpu sw freq

---
 .../esp_hw_support/port/esp32s2/rtc_clk.c     | 52 ++++++++++++++++---
 components/soc/esp32s2/include/soc/rtc.h      |  3 ++
 2 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/components/esp_hw_support/port/esp32s2/rtc_clk.c b/components/esp_hw_support/port/esp32s2/rtc_clk.c
index 8a11266efb..540fa0a567 100644
--- a/components/esp_hw_support/port/esp32s2/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32s2/rtc_clk.c
@@ -275,25 +275,52 @@ void rtc_clk_bbpll_configure(rtc_xtal_freq_t xtal_freq, int pll_freq)
  */
 static void rtc_clk_cpu_freq_to_pll_mhz(int cpu_freq_mhz)
 {
-    int dbias = DIG_DBIAS_80M_160M;
     int per_conf = DPORT_CPUPERIOD_SEL_80;
     if (cpu_freq_mhz == 80) {
         /* nothing to do */
     } else if (cpu_freq_mhz == 160) {
         per_conf = DPORT_CPUPERIOD_SEL_160;
     } else if (cpu_freq_mhz == 240) {
-        dbias = DIG_DBIAS_240M;
         per_conf = DPORT_CPUPERIOD_SEL_240;
     } else {
         SOC_LOGE(TAG, "invalid frequency");
         abort();
     }
+
+    /* To avoid the problem of insufficient voltage when the CPU frequency is switched:
+     * When the CPU frequency is switched from low to high, it is necessary to
+     * increase the voltage first and then increase the frequency, and the frequency
+     * needs to wait for the voltage to fully increase before proceeding.
+     * When the frequency of the CPU is switched from high to low, it is necessary
+     * to reduce the frequency first and then reduce the voltage.
+     */
+
+    rtc_cpu_freq_config_t cur_config;
+    rtc_clk_cpu_freq_get_config(&cur_config);
+    /* cpu_frequency < 240M: dbias = DIG_DBIAS_XTAL_80M_160M;
+     * cpu_frequency = 240M: dbias = DIG_DBIAS_240M;
+     */
+    if (cpu_freq_mhz > cur_config.freq_mhz) {
+        if (cpu_freq_mhz == 240) {
+            REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, DIG_DBIAS_240M);
+            REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DBIAS_WAK, RTC_DBIAS_240M);
+            esp_rom_delay_us(40);
+        }
+    }
+
     REG_SET_FIELD(DPORT_CPU_PER_CONF_REG, DPORT_CPUPERIOD_SEL, per_conf);
     REG_SET_FIELD(DPORT_SYSCLK_CONF_REG, DPORT_PRE_DIV_CNT, 0);
-    REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, dbias);
     REG_SET_FIELD(DPORT_SYSCLK_CONF_REG, DPORT_SOC_CLK_SEL, DPORT_SOC_CLK_SEL_PLL);
     rtc_clk_apb_freq_update(80 * MHZ);
     ets_update_cpu_frequency(cpu_freq_mhz);
+
+    if (cpu_freq_mhz < cur_config.freq_mhz) {
+        if (cur_config.freq_mhz == 240) {
+            REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, DIG_DBIAS_XTAL_80M_160M);
+            REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DBIAS_WAK, RTC_DBIAS_XTAL_80M_160M);
+            esp_rom_delay_us(40);
+        }
+    }
 }
 
 bool rtc_clk_cpu_freq_mhz_to_config(uint32_t freq_mhz, rtc_cpu_freq_config_t* out_config)
@@ -446,6 +473,9 @@ void rtc_clk_cpu_freq_set_xtal(void)
  */
 void rtc_clk_cpu_freq_to_xtal(int freq, int div)
 {
+    rtc_cpu_freq_config_t cur_config;
+    rtc_clk_cpu_freq_get_config(&cur_config);
+
     ets_update_cpu_frequency(freq);
     /* Set divider from XTAL to APB clock. Need to set divider to 1 (reg. value 0) first. */
     REG_SET_FIELD(DPORT_SYSCLK_CONF_REG, DPORT_PRE_DIV_CNT, 0);
@@ -454,18 +484,24 @@ void rtc_clk_cpu_freq_to_xtal(int freq, int div)
     /* switch clock source */
     REG_SET_FIELD(DPORT_SYSCLK_CONF_REG, DPORT_SOC_CLK_SEL, DPORT_SOC_CLK_SEL_XTAL);
     rtc_clk_apb_freq_update(freq * MHZ);
-    /* lower the voltage */
-    if (freq <= 2) {
-        REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, DIG_DBIAS_2M);
-    } else {
-        REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, DIG_DBIAS_XTAL);
+
+    /* lower the voltage
+     * cpu_frequency < 240M: dbias = DIG_DBIAS_XTAL_80M_160M;
+     * cpu_frequency = 240M: dbias = DIG_DBIAS_240M;
+     */
+    if (cur_config.freq_mhz == 240) {
+        REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, DIG_DBIAS_XTAL_80M_160M);
+        REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DBIAS_WAK, RTC_DBIAS_XTAL_80M_160M);
+        esp_rom_delay_us(40);
     }
 }
 
 static void rtc_clk_cpu_freq_to_8m(void)
 {
+    assert(0 && "LDO dbias need to modified");
     ets_update_cpu_frequency(8);
     REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, DIG_DBIAS_XTAL);
+    esp_rom_delay_us(40);
     REG_SET_FIELD(DPORT_SYSCLK_CONF_REG, DPORT_PRE_DIV_CNT, 0);
     REG_SET_FIELD(DPORT_SYSCLK_CONF_REG, DPORT_SOC_CLK_SEL, DPORT_SOC_CLK_SEL_8M);
     rtc_clk_apb_freq_update(RTC_FAST_CLK_FREQ_8M);
diff --git a/components/soc/esp32s2/include/soc/rtc.h b/components/soc/esp32s2/include/soc/rtc.h
index 1503f34892..afeb4dd931 100644
--- a/components/soc/esp32s2/include/soc/rtc.h
+++ b/components/soc/esp32s2/include/soc/rtc.h
@@ -96,7 +96,10 @@ extern "C" {
 #define DIG_DBIAS_80M_160M  RTC_CNTL_DBIAS_1V10
 #endif
 #define DIG_DBIAS_240M      RTC_CNTL_DBIAS_1V25
+#define RTC_DBIAS_240M      RTC_CNTL_DBIAS_1V25
 #define DIG_DBIAS_XTAL      RTC_CNTL_DBIAS_1V10
+#define DIG_DBIAS_XTAL_80M_160M  RTC_CNTL_DBIAS_1V10
+#define RTC_DBIAS_XTAL_80M_160M  RTC_CNTL_DBIAS_1V10
 #define DIG_DBIAS_2M        RTC_CNTL_DBIAS_1V00
 
 #define RTC_CNTL_PLL_BUF_WAIT_DEFAULT  20